What is the lumbar spinal canal?

Anyone who has some common sense about the human body structure knows that the lumbar spine plays a very important role in the human body. However, because the lumbar spine is composed of a series of lumbar vertebrae, it is also a very fragile part. Moreover, the distribution of nerves and blood vessels around the lumbar spine is also very complex and diverse. One of these components is the lumbar spinal canal. So where is the lumbar spinal canal mainly located on the lumbar spine?

Composition and form

1. The composition of the vertebral canal wall: The vertebral canal is a bone fibrous tube. Its anterior wall is composed of the back of the vertebral body, the posterior edge of the intervertebral disc and the posterior longitudinal ligament, the posterior wall is composed of the vertebral lamina, the yellow ligament and the articular process joints, and the lateral walls are the pedicles and intervertebral foramina. The sacral segment of the spinal canal is connected by the vertebral foramina of the sacral vertebrae and is a bony canal. Any lesions in the structures that make up the spinal canal wall, such as vertebral bone hyperplasia, intervertebral disc herniation, and hypertrophy of the yellow ligament, can cause the spinal canal to deform or narrow, compressing its contents and causing a series of symptoms.

2. The shape of the spinal canal cavity is not exactly the same in shape and size in cross-section. The upper part of the cervical segment is approximately circular near the foramen magnum, and is triangular downward, with a short sagittal diameter and a long transverse diameter; the thoracic segment is roughly circular; the upper and middle parts of the lumbar segment are triangular, and the lower part is trilobate; the sacral segment is a flat triangle. The spinal canal is narrowest at the 4th to 6th thoracic vertebrae, and is smallest at the 7th cervical vertebra in the cervical segment and the 4th lumbar vertebra in the lumbar segment.

Spinal stenosis

Congenital spinal stenosis is caused by congenital stenosis of the spinal canal during the growth and formation of the spine, including nutritional trauma and other factors. Most patients are asymptomatic at first, but after middle age, some degenerative lesions or injuries of the spine lead to symptoms and signs of spinal stenosis. Acquired spinal stenosis is caused by intervertebral disc herniation, vertebral hyperplasia, vertebral slippage, and hyperplasia, thickening, calcification or ossification of the posterior longitudinal ligament and yellow ligament, which stimulate the spinal nerves and surrounding blood vessels, causing inflammation, adhesion, congestion and edema of the nerves and blood vessels, thereby leading to spinal stenosis.